DATA TYPES
Binary
	• Computers store data as binary using switches (on/off maps to 1/0
	• Can represent numbers, text (using ASCII or Unicode), images (pixels) or sound
	• Sign and magnitude or two's complement to represent negative numbers
	• Subtraction - convert to two's complement and add
Hexadecimal
	• More visually compact
	• Easier for humans to read and remember
	• Easy to convert from binary and vice versa (4 bits = 1 hex digit)
	• Uses
		○ Colour codes e.g. #FF5733
		○ Memory addresses
		○ Mac addresses
Floating-point binary
	• Purpose of normalisation
		○ Ensures maximum precision e.g. mantissa of 0.001011101 is stored as 0.00101 unnormalised with a 5 bit mantissa but 0.10111 normalised
		○ Ensures each number has a unique representation so they can be compared easily
Logical shifts
	• Logical shift left - pad with 0, multiplies number by 2
	• Logical shift right - pad with 0, divides number by 2
Bitwise operators and masks
	• AND - used to set specific bits to 0
	• OR - used to set specific bits to 1
	• XOR - used to toggle specific bits
Character sets
	• A character set is a standard list of characters with a unique binary number assigned to each
	• Ensures that computers store and interpret text consistently and allows different devices to communicate clearly
	• ASCII uses 7 bits so can store 27 = 128 characters
	• Unicode uses more bits so can store far more characters, allowing it to store characters from different languages, symbols, and emojis

DATA STRUCTURES
Arrays, records, lists and tuples
	• A data structure is an ordered collection of items under a single identifier
	• Arrays
		○ Static (fixed-length), mutable (items can change), can only store one data type
		○ Stored in contiguous memory - CPU can move through them really quickly
		○ Static - memory straight after it can be allocated to something else 
	• Records
		○ Mutable, static
		○ Store different types of data about one thing
		○ Like a database table row, with each different item being a field
		○ Each field can only store data of one type, but different fields can store different data types
	• Tuples
		○ Immutable, static, can store different data types
		○ Used when data needs to be kept constant
		○ Static - memory straight after it can be allocated to something else
	• Lists
		○ Mutable, dynamic (length can change) and can store different data types
		○ Storage required is unknown initially - less memory efficient
		○ Often requires extra memory for pointers
		○ More difficult to program

BOOLEAN ALGEBRA